1. GREEN, C. H., Geophysics, 3, p. 295, 1938.
2. TELFORD, W. M., GELDART, L. P., SHERIFF, R. E. and KEYS, D. A., Applied geophysics, p. 352, Cambridge Univ. Press, Cambridge, 1976.
3. Dix, C. H., Geophysics, 20, p. 68, 1955.
4. MAYNE, W. H., Geophysics, 27, p. 927, 1962.
5. DURBAUM, H., Geophys. Prospecting, 2, p. 151, 1954.